Proteins and other large biological molecules, including DNA, may be separated for analysis using electrophoresis techniques. One particularly important application of these techniques is the sequencing of the DNA and RNA molecules. In performing an electrophoresis separation of such molecules, a gel is formed between two non-conducting plates, such as glass, to form a thin sheet of gel between the glass surfaces. The surfaces at either end of the gel are each connected to a buffer reservoir which serve as electrodes. A potential is applied across the gel by connecting each reservoir to opposite polarities of a voltage source. The electrophoresis gel layer is typically formed between two glass plates in an electrophoresis cassette. Exemplary cassettes are shown in U.S. Pat. No. 4,576,693 and U.K. Patent Application 2,180,941A.
It is extremely important during the assembly of such cassettes that all dirt and other foreign objects be kept out of the gel layer and that the gel layer be uniform and bubble free. To assemble an electrophoresis cassette and fill it with gel material typically requires substantial training and practice on the part of a technician. In particular, filling the cassette with the electrophoresis gel requires skill and considerable time. The present invention is directed at apparatus for filling a gel cassette.